Transcript genetic engineering - OG

15.1 SELECTIVE BREEDING
(Hybridization vs. Inbreeding;
biotechnology)
• Hunters in the 1800’s needed a hunting
dog that was big, strong, fast, and
aggressive
• However, no dog like this existed at
that time
• They knew of two species of dogs, each
with some of the desired qualities
• Can they somehow combine the two
into one?
Big and strong, but lacked Fast and aggressive,
but lacked strength
speed and aggression
Big, strong,
fast, and
aggressive
Why use selective breeding?
• Humans use selective breeding, which
takes advantage of naturally
occurring genetic variation, to pass
wanted traits on to the next generation
of organisms
• What ways can humans selectively
breed plants or animals?
2 Types of Selective Breeding
Hybridization
• Crossing dissimilar
individuals to bring
together the best of
both worlds
• American botanist Luther
Burbank selectively bred
800 plants, called varieties
• Many varieties can be
found in your supermarket!
• Bred for size, disease
resistance, flowering,
taste, color and a variety
of other reasons based on
preference
Inbreeding
• Crossing breeds of
individuals with
similar
characteristics
• Maintains traits of
that breed
(purebreds)
• Risky – increases
chance for mutation
since individuals are
very genetically
similar to each other
Hybridization
• Hybridization occurs in both plants and
animals
• Creating hybrid plants is different than
creating hybrid animals
• Animals can be sterile if their chromosome
number is odd, or if there are too many
mutations that occur when they breed
naturally (rarely occurs in the wild)
• Plants can be bred easily by gardeners or
botanists
• Many crops today are hybrids (can sometimes
occur naturally in the wild)
Genetically-Engineered
Hybrid Plants
• You have probably eaten many GE
plants without realizing it.
Examples include:
• Seedless grapes/ watermelons
• Bananas, which commonly have
polyploidy (extra sets of
chromosomes – stronger, bigger)
• Corn – modern corn was
selectively bred from
teosinte at least 6,000
years ago
Can you guess these
hybrid fruits?
• Limequats
– Lime x Kumquat
• Tangelo
– Tangerine x Pomelo
Hybridization
• Hybridized animals are called hybrids
• Can you identify these hybrids?
http://www.youtube.com/watch?v=1zOWYj59BXI
•
•
WEBSITE: http://www.dogbreedinfo.com/hybriddogs.htm
List of Hybrid Dogs (Designer Dogs) (Boutique Dogs)
•
The word ”hybrid,” when referring to genetics means, “the offspring of genetically
dissimilar parents or stock, especially the offspring produced by breeding plants or
animals of different varieties, species, or races.” In general, the word means, “something
of mixed origin or composition.” Hybrid dogs, or designer dogs as some call them, are
becoming quite popular. Below is a list of the most popular hybrid dogs. The best way to
determine the traits of a mixed breed is to look up all breeds in the cross and know you
can get any combination of any of the characteristics found in all breeds. The Dog Breed
Info Center® does not attempt to interpret the temperaments of each individual hybrid
mix because the differences in the dogs, even within the same litter, can vary greatly. If
you do not feel the temperament of one of the purebreds in the mix is suited for your
lifestyle, then that hybrid dog is not for you. Do not take a gamble that the puppy or dog
will turn out like the other breed in the mix. Choosing a dog simply for its looks is a
foolish way to choose a dog. Read the article on Designer Dogs for more info on these
mixed breeds.
Please Note: A hybrid dog is not a BREED; it is a hybrid, which means it is a mix of
more than one purebred dog.
Scientifically speaking, the term "hybrid” is incorrect as all dogs are a sub-species
of wolf (Canis lupus familiaris) and as such, it is impossible to have a hybrid as they
are two of the same species. Although technically incorrect, the term "hybrid" is the
name which is predominantly used for these mixes and therefore it is the name we will
also use when referring to them.
•
•
Designer Doggies
• Aussiedoodle
Australian shepherd x
Poodle
• Cavapoo
Cavalier King Charles x
Poodle
• Cheagle
Chihuahua x
Beagle
•
•
WEBSITE: http://www.dogbreedinfo.com/hybriddogs.htm
List of Hybrid Dogs (Designer Dogs) (Boutique Dogs)
•
The word ”hybrid,” when referring to genetics means, “the offspring of genetically
dissimilar parents or stock, especially the offspring produced by breeding plants or
animals of different varieties, species, or races.” In general, the word means,
“something of mixed origin or composition.” Hybrid dogs, or designer dogs as some
call them, are becoming quite popular. Below is a list of the most popular hybrid dogs.
The best way to determine the traits of a mixed breed is to look up all breeds in the
cross and know you can get any combination of any of the characteristics found in
all breeds. The Dog Breed Info Center® does not attempt to interpret the temperaments
of each individual hybrid mix because the differences in the dogs, even within the same
litter, can vary greatly. If you do not feel the temperament of one of the purebreds in
the mix is suited for your lifestyle, then that hybrid dog is not for you. Do not take a
gamble that the puppy or dog will turn out like the other breed in the mix. Choosing
a dog simply for its looks is a foolish way to choose a dog. Read the article on Designer
Dogs for more info on these mixed breeds.
Please Note: A hybrid dog is not a BREED; it is a hybrid, which means it is a mix of
more than one purebred dog.
Scientifically speaking, the term "hybrid” is incorrect as all dogs are a sub-species
of wolf (Canis lupus familiaris) and as such, it is impossible to have a hybrid as they
are two of the same species. Although technically incorrect, the term "hybrid" is the
name which is predominantly used for these mixes and therefore it is the name we will
also use when referring to them.
•
•
Inbreeding
• Inbreeding uses two genetically similar organisms,
each being “the best of the best”
• Dog breeds are maintained by inbreeding
• Characteristics that are unique to each breed are
preserved
•Very prevalent in cattle
farming – gives farmers
the best possible
livestock
•Also can be very
dangerous if two
individuals have an
underlying mutation
Biotechnology
• Biotechnology - when scientists purposely
change the genetic makeup of an organism
(Ex: introduce a mutation)
• Used in agriculture and medicine
• Bacterial mutations
A strain of bacteria has been
developed that can digest oil to
help clean oil spills
Scientists are trying to produce
bacteria to clean up radioactive
waste
Combining DNA Fragments
• Since DNA is a universal code, it can be
combined from 2 or more sources
• Changes the genetic composition of the living
organism
• This is called recombinant DNA
• Can also be used to make proteins like human
insulin, hepatitis B vaccine, and a clotting
factor for hemophilia patients
Transgenic Organisms
• Scientists find specific genes and can add
them to any organism
• Organisms with genes from other species are
called transgenic organisms
• Ex: Red Fluorescent Protein (RFP) in cats
• Cat with the GFP is red under UV light, while a
normal cat glows green
• How did they do that…?
http://www.youtube.com/watch?v=
YVdLJ78RBWk
Cloning
• A clone is a member of a population of
genetically identical cells produced from
a single cell
Genetic Modification
• If you’ve eaten corn, potatoes, or soy products
this week, chances are you’ve eaten
genetically modified (GM) food – it doesn’t
have to be recorded on food labels!
• Many plants are genetically modified
• Resistance to insects, herbicides (weed killer),
and viral infections
• Resistance to rot or spoilage
Genetically Modified Animals
• 30% of milk in US comes from cows injected
with hormones to increase milk production
• Pigs – produce more lean meat or high levels
of healthy omega-3 acids
• Salmon – faster growth to produce more fish
• Scientists in Canada combined spider genes
into lactating goats – produced silk along with
their milk. Silk was extracted and used to
make military uniforms, medical sutures, and
tennis racket strings
Genetic Modification
Good or Bad?
• Ideally, GM plants and animals could lead to
better, less expensive, and more nutritious
food as well as less-harmful manufacturing
processes
• Farmers and ranchers hope cloning will allow
them to duplicate prize animals, providing
better quality and more food to a rising
population
Recombinant DNA & Human Health
• Scientists can develop recombinant DNA to
produce human antibodies to fight disease
• Can also make proteins engineered in
transgenic sheep and pigs’ milk to be used in
disease prevention
• Can treat diseases caused by protein
deficiency
• Do you know of a disease/disorder caused by
protein deficiency?
Gene Therapy
• Gene therapy – process of changing a gene to
treat a medical disease/disorder
• Bad gene is replaced with a good gene
• 1st – need a virus to transport the gene into
the organism
• 2nd – patient’s cells are infected with the new
gene, hopefully correcting the defect
• Challenging part – Will it last long term? Will
the virus DNA harm the patient?